For lowering the end of each telescopic beam to the ground, the jacking system comprises a tilting mechanism, with a pivot support with a horizontal pivot axis around which the telescopic beam at the vehicle body can be inclined, and a support drive with a telescopic drive element, for example, a hydraulic cylinder. A first end of the telescopic drive element is pivotably attached to the vehicle body, and its opposite end is supported at the telescopic beam at a position between the pivot support and the support end of the telescopic beam. With other words, the telescopic beam is hinged to the vehicle body at the side opposite to the extracted outer support end, while the support drive is arranged to lower the outer support end to the ground by extracting the telescopic drive element. When the outer support end of the beam touches the ground, further actuation of the support drive acts to lift the vehicle body from its wheel suspensions and to take the reaction force from the ground. With multiple support beams at different positions around the vehicle, a safe stand of the system is provided.
Although this system works satisfactorily, certain problems are experienced with the load transmission from the ground into the vehicle body. Because of the relatively high attachment point of the telescopic drive element at the vehicle body, cross forces acting in a direction mainly perpendicular to the extension direction of the telescopic beam (i.e. parallel to the driving direction of the vehicle) are introduced into the telescopic drive element and its attachment points. Such cross forces occur typically in a situation in which the vehicle body is jacked on a ground that has a strong inclination in the driving direction of the vehicle, for example, on a street with a strong upward or downward slope. These cross forces act laterally as shear forces or bending forces on the extension mechanism of the telescopic drive element, leading to poor stability and increased wear of its moving parts, and impairing its guiding properties in lifting or lowering the telescopic beam because of undesired tolerance in its components and their mutual interaction.
Moreover, cross forces acting in a generally horizontal direction along the telescopic beam are introduced mainly at the pivot support, at the opposite side of the vehicle body, because they cannot be fully absorbed by the telescopic drive element which has a relatively strong inclination with respect to the horizontal plane and the telescopic beam. For reasons of constructional design, it is difficult or at least disadvantageous to introduce these forces into the lower part of the frame work of the vehicle body.